Herbicidal N-haloacetyl-1,2-dihydro-4H-3,1-benzoxazine

ABSTRACT

Novel N-haloacetyl-1,2-dihydro-4H-3,1-benzoxazines which have utility as herbicides.

United States Patent Kobzina Nov. 4, 1975 HERBICIDAL [56] References: Cited N-HALOACETYL-1,2-DIHYDRO-4H-3,1- OTHER PUBLICATIONS BENZOXAZINE [75] Inventor: John W. Kobzina, Walnut Creek, Chem. Abst., 76 3772(h), (1972), Artico et a].

Calif. Chem. Abst., 78 84,336(k), (1973), Hekenbrock et [73] Assignee: Chevron Research Company, San

Francisco Calif Primary Examiner-Albert T. Meyers [22] Filed: Sept. 27, 1974 Assistant ExaminerD. W. Robinson Attorney, Agent,- or FirmJ. A. Buchanan, Jr.; Dix A. [21] Appl. No.. 509,979 Newen; Raymond y g [52] US. Cl. 260/244; 71/66; 71/77; 57 T A 424/248 Novel N-haloaCetyl-l ,2-dihydro-4H-3 ,1 benzoxazines [51] Int. Cl. .....C07D 265/00; C07D 273/00;2(9'J50/Z)]3 which have utility as herbicides AOlN 9/00 [58] Field of Search 260/244; 71/66, 67; l Clalms, No r wings HERBICIDAL N-HALOACETYL- 1 ,2-DIHYDRO-4H-3,l-BENZOX- AZINE DESCRIPTION OF THE PRIOR ART South African Pat. No. 6808449 [Chem Abst. 72 79064s (1970)] discloses N-acetyl-3,4-dihydro-lI-l- 2,3-benzoxazines which have antiinflammatory activity.

British Pat. No. 1,137,796 [Chem. Abstr. 7O 106539t (1969)] discloses N-haloacylated 3,4-dihydro-2I-l-l,4- benzoxazines which are intermediates for the preparation of N-aminoacyl-3,4-dihydro-2H-l ,4-benzoxazines.

US Pat. No. 3,519,624 discloses N-haloacetyl-l,2- dihydro-l,3-benzoxazines which have antimicrobial, bactericidal and fungicidal properties.

DESCRIPTION OF THE INVENTION The herbicidal N-haloacetyll ,2-dihydro-4H-3 l benzoxazine compounds of the invention are represented by the formula (I):

wherein X is fluoro, chloro or bromo; Y is hydrogen, fluoro, chloro or bromo; R R R and R individually are alkyl of l to 6 carbon atoms, preferably of l to 3 carbon atoms; R is chloro, bromo or alkyl of 1 to 6 carbon atoms; and n is 0, 1 or 2.

Preferably R is alkyl of l to 6 carbons, more preferably of l to 3 carbon atoms. Most preferably R is at the 8th position of the benzoxazine ring. Preferably n is 0 or 1. Preferably Y is hydrogen.

In part because of their utility for the control of aquatic weeds, a preferred class of compounds of formula (I) is that wherein X is bromo. In this preferred class, Y is preferably hydrogen or bromo, more preferably hydrogen.

Representative compounds of formula (I) include:

l-dibromo acetyl- 1 ,2-dihydro-4H-3,1-benzoxazine l-trichloroacetyl- 1 ,2-dihydro-4H- 3 1 -benzoxazine l-chloroacetyl-7,8-dimethyl-1 ,2-dihydro-4H-3, l

benzoxazine l-fluoroacetyl-S ,6-dichlorol ,2-dihydro-4H-3, l-benzoxazine l-chloroacetyl-2,4-dipropyll ,2-dihydro-4I-I-3, lbenzoxazine v l-chloroac etyI-S-chloro- 8-methyl-1,2-dihydro-4I-I- 3,1-benzoxazine and l-dichloroacetyl-7-methyll ,2-dihydro-4H-3,1-benzoxazine.

The compounds of the invention are prepared as depicted in reactions 1 and 2:

0 R. x R R (Ill) OH (I) H l N /R 15 R R H 0 RZI R4 (IV)+XY2C(|Z|X+B (I)+B.HX 2

wherein X, Y, R, R R R, R and n have the same significance as previously defined, and B is an acid acceptor.

The condensation reaction l is conducted by reacting the aminobenzyl alcohol (II) with the aldehyde or ketone (III) at a temperature of 0 to 100C. in an inert diluent. Generally, at least one mol of aldehyde or ketone (III) is used per mol of alcohol (II). The benzoxazine product (IV) is isolated by conventional procedures such as extraction, distillation or chromatogra- P y- The alkylation reaction (2) is conducted by contacting the benzoxazine (IV), the haloacetyl halide (V) and the acid acceptor in an inert diluent at a temperature of about 0C. to 100C. The reactants (IV) and (V) and the acid acceptor are generally used in substantially equimolar amounts, although an excess of the acid acceptor may be used. Suitable acid acceptors include trialkylamines and pyridine compounds. The product (I) is isolated and purified by conventional procedures such as extraction, distillation, chromatography, crystallization, etc.

EXAMPLES Example 1 Preparation of l-chloro acetyl-4,4-dim ethyl-l ,2-dihydro-4l-l-3, 1-benzoxazine ll CICHQCI N i O CH/ \CHa A 30.2-g (0.2 mol) sample of methyl 2-aminobenzoate in 150 ml diethyl ether was added dropwise to a solution of methyl magnesium iodide (prepared from 19.4 g of Mg and 127.8 g of methyl iodide) in 150 ml diethyl ether. The reaction mixture was then heated under reflux for 1 hour, cooled, and diluted with 200 ml of saturated aqueous ammonium chloride solution. The resulting aqueous mixture was extracted with ether. The ether extracts were dried over magnesium sulfate and evaporated to give 19.1 g of a,a-dimethyl- 2-aminobenzyl alcohol.

An 8.25-ml solution of 37% aqueous formaldehyde (0.099 mol) was added over 5 mintues to a cooled (0C.) mixture of g (0.066 mol) a,a-dimethyl-2- aminobenzyl alcohol in 50 ml water. The reaction mixture was then diluted with 50 ml benzene and vigorously stirred for 5 minutes. The aqueous layer was separated and extracted with benzene. The benzene layer of the reaction mixture and the benzene extracts were combined, dried over magnesium sulfate and evaporated. The resulting oil was distilled through a short column'to give 6.3 g (b.p. 120-125C. at 0.1 mm of Hg) of 4,4-dimethyl-1 ,2-dihydro-4l-I-3, 1 -benzoxazine, as a colorless oil. Elemental analysis showed: %C, calc. 73.6, found 68.3: %l-l, calc. 8.0, found 7.6; %N, calc. 8.6, found 8.6.

A solution of 1.73 g (0.015 mol) a-chloroacetyl chloride in 5 ml methylene chloride was added dropwise to a solution of 2.5 g (0.015 mol) 4,4-dimethyl-l,2-dihydro-4I-l-3,l-benzoxazine and 1.55 g (0.015 mol) triethylamine in 75 ml methylene chloride. The reaction mixture was stirred at about 25C. for 2 hours, washed with water, dried over magnesium sulfate and evaporated to give a crystalline solid. The solid was washed with ether-hexane and dried to give 2.75 g of l-chloroacetyl-4,4-dimethyl-1,2-dihydro-4I-l-3, 1 -benzoxazine, m.p. 8084C, as a brown solid.

Example 2 Preparation of 1-chloroacetyl-2,2,4,4-tetramethyl- 1 ,2-dihydro-4H- 3 1 -benzoxazine dihydro-4I-I-3,l-benzoxazine and 2.64 g (0.026 mol) triethylamine in ml methylene chloride. The reaction mixture was stirred at about 25C. for 1.5 hours, washed with water, dried over magnesium sulfate and evaporated. The residue was chromatographed on silica gel (20% ether-% hexane eluant) to give 3.0 g of 1-chloroacetyl-2,2,4,4-tetramethyl- 1 ,2-dihydro-4I-l- 3,1-benzoxazine, m.p. 52-57C., as a white solid.

Other compounds of the present invention were prepared by procedures similar to the above examples.

These compounds and the compounds of Examples 1 and 2 are tabulated in Table I.

UTILITY The compounds of the present invention are, in general, herbicidal in both preand post-emergent applications. For pre-emergent control of undesirable vegetation, the herbicidal compounds will be applied in herbicidally effective amounts to the locus or growth medium of the vegetation, e.g., soil infested with seeds and/or seedlings of such vegetation. Such application will inhibit the growth of or kill the seeds, germinating seeds and seedlings. For post-emergent applications, the herbicidal compounds will be applied directly to the foliage and other plant parts. Generally, the herbicidal compounds of the invention are effective against weed grasses as well as broadleaved weeds. Some may be selective with respect to the type of application and- /or type of weed.

The compounds of the present invention can be used alone as herbicides. However, it is generally desirable to apply the compounds in herbicidal compositions comprising one or more of the herbicidal compounds intimately admixed with a biologically inert carrier. The carrier may be a liquid diluent or a solid, e.g., in the form of dust powder or granules. In the herbicidal composition, the active herbicidal compounds can be from about 0.01 to by weight of the entire composition.

Suitable liquid diluent carriers include water and organic solvents, e.g., hydrocarbons such as benzene, toluene, kerosene, diesel oil, fuel oil, and petroleum naphtha. Suitable solid carriers are natural clays such as kaolinite, atalpulgite, and montmorillonite. In addition, talcs. pyrophillite, diatomaceous silica, synthetic fine silicas, calcium aluminosilicate and tricalcium phosphate are suitable carriers. Organic materials such as walnut-shell flour, cottonseed hulls, wheat flour, wood flour or redwood-bark flour may also be used as solid carriers.

The herbicidal composition will also usually contain a minor amount of a surface-active agent. Such surface agents are those commonly known as wetting agents, dispersing agents and emulsifying agents, and can be anionic, cationic or nonionic in character. The herbicidal compositions may also contain other pesticides, adjuvants, stabilizers, conditioners, fillers, and the like.

The amount of herbicidal compound or composition administered will vary with the particular plant part or plant growth medium which is to be contacted, the general location of application i.e., sheltered areas such as greenhouses, as compared to exposed areas such as fields as well as the desired type of control. Generally for both preand postemergent control, the herbicidal compounds of the invention are applied at rates of 0.2 to 60 kg/ha, and the preferred rate is in the range 0.5 to 40 kg/ha.

Preand post-emergent herbicidal tests on representative compounds of the invention were made using the following methods:.

zines, are useful for controlling aquatic weeds such as Euglena, Spirogyra, Nitella, Lemna, Elodea, Hornwort and Azolla. They may be used to control such aquatic weeds in aqueous bodies such as lakes, streams, canals,

Pre'Emergem Test 5 pools, aqueous industrial effluents, cooling towers, and An acetone solution of the test compound was prethe like. When so used, a biocidal quantity of one or pared by mixing 750 mg of the compound, 220 mg of a more of the N-bromoacetylbenzoxazines of the invennonionic surfactant and 25 ml of acetone. This solution tron 18 added to the aqueous growth environment of the was added to approximately 125 m1 of water containing weeds. Usually, this dosage will range between about 156 mg of surfactant 10 0.1 and 10 ppm. These compounds may be applied to Seeds of the test vegetation were planted in a pot of the aqueous growth environments of such weeds as dissoil and the test solution was sprayed uniformly onto persible powders or in solution with water-miscible solthe soil surface at a dose of 33 meg/cm? The pot was vents, watered and placed 111 a greehhouse- The P was w 15 Representative N-bromoacetylbenzoxazines of this teted lhtetmlttehtly ahd w 'f for seedhhg invention were tested as algicides by the following hs health of s g sesdhhgs t method. An acetone solution of the test compound and week P At the end of thls pehod the hetblcldal a surfactant was prepared. This solution was mixed effestwehess Ofthe I p d was rated based on the with a nutrient brothin a quantity sufficient to give a p y l h Observatlohs-A 040-100 scale was used, 20 concentration of 2 ppm test compound. Three 150-ml p e g ho phytotoxlclty, 100 repress-hung specimen cups were filled with this mixture. Samples of plete kill. The results of these tests appear 1n Table ll. the test algae were added to each Specimen cup and the PosLEmergem Test cups were then placed in an environment chamber for incubation. The cups were observed periodically for The test chmpouhd was formulated the same 25 alga growth. The algicidal effectiveness of the test comher s desctlbed 91" for the P 's test- T pound was determined based on a final observation of concentration of the test compound in this formulation alga growth ft 3 days h results f these tests, was Q Q PP This fth'mutatloh was uhlfonhly sp ported as the average of the 3 specimen cups on a O-to- 0h 2 slhhlar P of 24 y- Pl pp i y 100 basis 0 indicating no effectiveness and 100indi- 15 to 25 Plants ps P at a dose of After eating complete effectiveness are reported in Table the plants had dried, they were placed in a greenhouse 30 [IL 1 TABLE 1 Melting Halogen point. Analysis No Compound C. Calc Found 1 l-chloroacetyl,4,4-dimethyl-1,2-dihydro-4H-3,[-benzoxazine 80-84 14.8 15 .8 2 1-bromoacetyl-4,4-dimethyl-1,2-dihydro-4l-l-3,l-benzoxazine 78-80.5 4.9* 5.1* 3 1-ch1oroacelyl-2,2,4,4-tetramethyl- 1 ,2-dihydro-4H-3, 1 -benzoxazine 52-57 13 .2 l 1,8 4 I-bromoacetyl- 1 ,2-dihydro-4H-3, 1 -benzoxazine Oil 31 .2 30.5 5 l-chloroacetyll ,2-dihydro-4l-l-3. l -benzoxazine Oil 16.8 18.5 6 l-chloroacetyl-2,2-dimethyl-1,2-dihydro-4l-l-3,l-benzoxazine 47-49 14.8 15 .4 7 l-chloroacetyl-2,4,4-trimethyl-l,2-dihydro-4H-3,1-benzoxazine Oil 14.0 14.3 8 l-chloroacetyl-2-ethyl-2,4,4-trimethy1-I ,2-dihydro-4H-3, 1 -benzoxazine Oil 12.6 12.0 9 l-bromoacety1-2,4,4-trimethyll,2-dihydro-4H-3,1-benzoxazine 54-56 26.8 26.6 10 1-chloroacetyl-2-methyl-1,2-dihydro-4H-3,l-benzoxazine Oil 15.7 15. l 1 l 1 -chloroacetyl-8-methyll ,2-dihydro-4H-3, 1 -benzoxazine 87-91 15.7 16.1 12 1-chloroacetyl-2,4,4-8-tetramethy1- l ,2-dihydro-4H-3, l-benzoxazine 64-66 13.2 13.0 1 3 1-bromoacety1-2,4,4,8 -tetramethyl- 1 ,2-dihydro-4H-3, l -benzoxazine 70-72 25.6 24.2 14 l-chloroacetyl-2-methyl-4,4-diethy1-l ,2-dihydro-4l-l-3 1 -benzoxazine Oil 12 .6 12.3 15 1-bromoacetyl-2-methyl-4,4-diethyl-1,2-dihydro-4l-l-3 1 -benzoxazine Oil 24.5 22 .7 16 l-chloroacetyl-Z,4-dimethyl-4-ethyl-1,2-dihydro-4H-3,l-benzoxazine Oil 13.2 12.2 17 1-chloroacetyl-2,4-dimethyl-4-ethyll ,2 -dihydro-4H-3, l -benzoxazine 39-41 14.8 14.9 18 l-bromoacety1-2,4-dimethyl'4-ethyll ,2-dihydro-4l-l-3, 1 -benzoxazine Oil 28.1 28.1 19 l-chloroacetyl-2,2,4-trimethyl-4-ethyl-l ,2-dihydro-4H-3, 1 -benzoxazine Oil 12.6 1 1 .3 20 1-chloroacetyl-Z-methy1-8-chloro-l ,2-dihydro-4l-l-3 1 -benzoxazine Oil 27 .2 .0 21 l-chloroacetyl-2,2,4-trimethyl-1.2-dihydr0-4H-3,l-benzoxazine 83-84 14.0 13 .6 22 1-bromoacetyl-2,2,4-trimethyl-1,2-dihydro-4H-3,l-benzoxazine 83-90 26.8 25 .0 23 l-chloroacetyl-2,8-dim ethyl-l ,2-dihydro-4l-l-3, l -benzoxazine 72-75 14.8 14.0 24 1-chloroacetyl-2-methyI-S-ethyl-1,2-dihydro-4H-3,l-benzoxazine Oil 14.0 12.8 25 l-chloroacetyl-2,4,4-trimethyl-l,2-dihydro-4l-l-3,l-benzoxazine 88-90 12.6 12.7 26 1-chloroacetyl-2,2 ,4,6-tetramethyll ,2-dihydro-4H-3 1 -benzoxazine Oil 13.2 12.3 27 1-chloroacetyl-2,6-dimethyl-l,2-dihydro-4H-3,l-benzoxazine Oil 14.8 14.8 28 1-chloroacetyl-4,4-dimethyl-8-ethyl-l ,2-dihydro-4H-3, l -benzoxazine 76-78 13.3 14.0

"Nitrogen analysis and then watered intermittently at their bases, as 0 TABLE II needed. The plants were observed periodically for phy- Herbicidal Effectiveness totoxic effects and physiological and morphological re- No 0 C M p L sponses to the treatment. After 3 weeks, the herbicidal I 25 30 25 effectiveness of the compound was rated based on 2 0 0 0 these observations. A O-to-lOO scale was used, 0 reprei 8 g {6* senting no phytotoxicity and 100 representing com- 5 0 55 25 75 2O plete kill. 6 10 75 o o o The compounds of the invention wherein X is bromo, Z g8 28 a g g g i.e., the N-bromoacetyl-l ,2-dihydro-4H-3,l-benzoxa- 9 10 75 0 10 o TABLE ll-continued Herbicidal Effectiveness No P L l0 0 I00 60 30 65 25 l l 83 I00 I00 0 I 25 I2 I00 I00 I00 95 I00 98 13 60 98 98 25 95 45 l4 I5 93 93 0 95 95 I5 35 20 3O 0 25 35 16 0 I00 95 0 O 90 17 0 98 I5 0 30 60 18 O 20* 0 35* 40 50 I9 '98 0 0 0 0 20 10 85 O 0 0 0 2] 10 I00 l5 l0 0 O 22 0 0 0 l0* l5* 23 0 90 70 0 0 0 24 85 30 0 0 0 25 55 100 I00 80 I00 90 26 10 80 0 0 0 0 27 0 95 0 0 0 0 28 93 I00 100 85 mo 93 Post-emergent test O=Wild Oats (Arenua falua) W=Watergrass (Ecliinocllloa crusgalli) Cirabgrass (Digimrin .s'angul'nalis) M=Mustard (Brassica arvensis) P=Pigweed (Amaramhus relmflexur) L= Lambsquarter (Chenopodium album) What is claimed is: l. A compound of the formula wherein X is fluoro, chloro or bromo, Y is hydrogen, fluoro, chloro, or bromo, R is hydrogen or alkyl of l to 6 carbon atoms, R? is hydrogen or alkyl of l to 6 carbon 15 atoms, R is hydrogen or alkyl of l to 6 carbon atoms, R is hydrogen or alkyl of l to 6 carbon atoms, R is chloro, bromo or alkyl of l to 6 carbon atoms, and n is O, l or 2. i

2. The compound of claim 1 wherein Y is hydrogen. 20 3. The compound of claim 2 wherein R is alkyl of l to 6 carbon atoms.

4. The compound of claim 2 wherein R is alkyl of 1 to 6 carbon atoms.

5.6The compound of claim 2 wherein R is alkyl of l 25 to 6 carbon atoms and R is alkyl of 1 to 6 carbon atoms. 1 i

6. The compound of claim 2 wherein R is alkyl of l to 6 carbon atoms and n is l.

7. The compound of claim 6 wherein R5 is substi- 30 tuted at the 8th position of the benzoxazine ring.

8. The compound of claim 2 wherein R is chloro or bromo and n is l. l

9. The compound of claim 1 which is l-Chloroacetyl- 4,4-dimethyl-8-ethyll ,2-dihydro-4H-3, l-benzoxazine. 10. The compound of claim 2 wherein X is bromo. 11. The compound of claim 10 which is l-Bromoacetyll ,2-dihydro-4H-3 1 -benzoxazine. 

1. A COMPOUND OF THE FORMULA
 2. The compound of claim 1 wherein Y is hydrogen.
 3. The compound of claim 2 wherein R1 is alkyl of 1 to 6 carbon atoms.
 4. The compound of claim 2 wherein R3 is alkyl of 1 to 6 carbon atoms.
 5. The compound of claim 2 wherein R3 is alkyl of 1 to 6 carbon atoms and R4 is alkyl of 1 to 6 carbon atoms.
 6. The compound of claim 2 wherein R5 is alkyl of 1 to 6 carbon atoms and n is
 1. 7. The compound of claim 6 wherein R5 is substituted at the 8th position of the benzoxazine ring.
 8. The compound of claim 2 wherein R5 is chloro or bromo and n is
 1. 9. The compound of claim 1 which is 1-Chloroacetyl-4,4-dimethyl-8-ethyl-1,2-dihydro-4H-3,1-benzoxazine.
 10. The compound of claim 2 wherein X is bromo.
 11. The compound of claim 10 which is 1-Bromoacetyl-1,2-dihydro-4H-3,1-benzoxazine. 